class_docstr: A class to open and interact with fits files from SDSS
  
  Parameters
  ----------
  buf : string or file buffer (optional)
      file path, buffer, or url of SDSS spectra fits file
      if None, then initialize an empty instance.
  
  Notes
  -----
  This class only provides access to a subset of the information available
  in the sdss spectra fits file.  The raw fits data can be accessed using
  the fits object directly.  This can be found in the attribute
  ``hdulist``.  For details, please refer to the data description:
  http://www.sdss.org/dr7/dm/flatFiles/spSpec.html
docstr: if i is specified, return log_w_min of bin i
  otherwise, return log_w_min of the spectrum
docstr_tok: ["if","i","is","specified",",","return","log_w_min","of","bin","i","otherwise",",","return","log_w_min","of","the","spectrum"]
code: def log_w_min(self, i=None):
      """
      if i is specified, return log_w_min of bin i
      otherwise, return log_w_min of the spectrum
      """
      if i is None:
          i = 0
      return self.coeff0 + (i - 0.5) * self.coeff1
  
imports: import gc
  import numpy
  from scipy.ndimage import gaussian_filter1d, uniform_filter1d
  from scipy import interpolate
  from .None import download_with_progress_bar
label_desc: Use image node_id 10 for calling the SDSSfits obj's underlying member method code with example usage: obj.log_w_min(i) and returns: unknown